1. Field of the Invention
This invention relates to an imaging element, and in particular to a silver halide photographic element with improved scratch and abrasion resistance.
It is conventional to incorporate an absorbing dye, in particular, an ultraviolet ray absorbing dye, into a light-insensitive layer in a photographic element to absorb light in a specific wavelength region. The dyed light-insensitive layer is used, f ample, to control the spectral composition of light incident upon a photographic emulsion layer, to act as an antihalation layer between the support and the photographic emulsion layer or on the side of the support opposite to the photographic emulsion layer to prevent halation caused by light scattering during and after the passage of light through the photographic emulsion layer. In addition, the dyed light-insensitive layer is used to absorb or to remove ultraviolet light produced by static discharge, which occurs when the surfaces of the photographic element come into contact during production or treatment processes. Electric charges are generated by friction of separation. When accumulation of static electricity by charging reaches a certain limiting value, atmospheric discharge occurs at a particular moment and a discharge spark fires at the same time. When the photographic element is exposed to light by discharging, static marks appear after development.
2. Description of Related Art
Different methods for incorporating absorbing dyes into a non-imaging layer have been described in, for example, U.S. Pat. Nos. 2,739,888, 3,352,681, and 3,707,375 where an oil soluble dye is dissolved in a high boiling organic solvent, and mixed under high shear or turbulence together with an aqueous medium, which may also contain a surfactant, and/or gelatin in order to break the organic phase into submicron particles dispersed in the continuous aqueous phase. However, when such dye dispersions are used in a light-insensitive layer, the layer becomes soft and the mechanical properties of the layer are lowered. Furthermore, many dyes themselves are liquid, and they therefore can have a detrimental effect on the mechanical properties of the layer and adhesion with the adjacent layer.
The weakening of light-insensitive layers by an absorbing dye dispersion, in particular by an ultraviolet absorbing dye dispersion, has been a serious problem in, for example, color light sensitive materials, where a light-insensitive layer containing an ultraviolet dye dispersion is often coated as a protective layer on the top of the emulsion layer to remove the ultraviolet light generated by static discharge and for correct color reproduction. Since it is desired to record only visible light, the influence of the ultraviolet light is very apparent. For example, when photographing objects which have a comparatively large quantity of spectral energy in the ultraviolet region, such as a distant view, a snow scene, or an asphalted road, etc. the resulting color images are rich in blue color. Accordingly, in order to obtain color photographic images which have correct color reproduction, it is desired to prevent ultraviolet rays from reaching the silver halide emulsion layers. Very often, another light-insensitive layer containing a matting agent is coated as the topmost layer above the light-insensitive layer containing the ultraviolet absorbing dye dispersions for better resistance to ferrotyping and sticking at high temperature and in moist environments. Photographic materials with such layer structures often show inferior physical and mechanical properties during various handling processes, such as coating, drying, finishing, winding, rewinding, printing, and so on. For example, the photographic material surfaces are easily harmed by contact friction with other apparatus and between their front and back faces. Scratches and abrasion marks can be generated. These generated scratches and abrasion marks deface the image during printing and projection processes. On irreplaceable negatives, the physical scratches may require very expensive retouching.
Various methods have been proposed to obtain a physically improved photographic material by reducing the contact friction of the photographic material to other surfaces so that it will not be damaged during the manufacturing, exposure, developing and printing or projecting processes. For example, methods for reducing the contact friction were described in U.S. Pat. No. 3,042,522 by incorporating both a silicone fluid and a certain surface active agent into the protective overcoat, in U.S. Pat. No. 3,080,317 by using a mixture of dimethyl silicone and diphenyl silicone on the backside of the support, in GB Patent No. 1,143,118 by incorporating a triphenyl terminated methyl phenyl silicone into the emulsion protective overcoat, in U.S. Pat. No. 3,489,567 by using a combination of dimethyl silicone and beta-alanine derived surfactants, in U.S. Pat. No. 3,121,060 by using modified sperm oils in the protective overcoat, in U.S. Pat. No. 4,004,927 by using liquid organopolysiloxane with methyl and alkyl (&gt;C.sub.1) or aryl, or aryalkyl side groups in the protective overcoat, and in U.S. Pat. No. 4,047,958 by using polysiloxane with polyether side chains on the backside of the support.
Various methods have also been proposed to reinforce the surface overcoat layer, for example, in GB Patent No. 1,270,578 by adding a certain class of hardener to gelatin, in U.S. Pat. No. 3,053,662 by using colloidal silica in the overcoat layer, in U.S. Pat. No. 4,268,623 by using colloidal silica in combination with a water soluble polymer having a carboxylic acid group in the overcoat layer, in U.S. Pat. No. 4,777,113 by using two overcoat layers, the upper layer containing a colloidal silica and the lower layer containing a polymer latex, and in U.S. Pat. No. 4,914,012 by using a composite latex comprising a polymeric acrylic acid ester and/or a polymeric methacrylate acid ester and colloidal silica. However, the use of colloidal silica particles in the surface protective layer suffers from a number of disadvantages; for example, they increase significantly the coating solution viscosities; they increase the brittleness of the protective layer; they adhere to wall surfaces and therefore give rise to extensive cleaning of equipment and increased labor cost; and they are highly abrasive and therefore may increase the wear of manufacturing and processing equipments.
In recent years, the conditions under which the photographic materials are manufactured or utilized have become even more severe, either because their applications have been extended, for example, in an atmosphere of high humidity and high temperature, or because the methods for their preparation have been advanced, for example, the use of high speed coatings, high speed finishing and cutting, and fast processing, or because their emulsion layers have been progressively thinned. Under these conditions, the aforementioned photographic materials are more severely scratched.